Paved roads are nice to look at, but they’re easily damaged and costly to repair. UV rays, weather, oxidation and constant traffic wear down paved surfaces, loosening rocks and creating dangerous potholes.
But are there better alternatives for paving roads than traditional asphalt? At TEDxDelft, civil engineer Erik Schlangen says yes. Here he demonstrates a new type of porous asphalt with an astonishing feature: When cracked, it can be “healed” by induction heating.
This “self-healing” asphalt is infused with tiny strands of steel wool (yes, that steel wool — the same used to scrub dishes), which clings to the binding of the asphalt, called bitumen. When Schlangen’s asphalt develops a crack, caretakers can use heat to melt the steel mixed in the bitumen, which then liquifies and flows into the road’s cracks, “healing” itself.
Onstage, Erik demonstrates this process by dropping a piece of his asphalt into liquid nitrogen, breaking it, and then heating it in a microwave to “heal it,” a process from which the asphalt reemerges fully formed. Out on the roadways, he and his team from the Delft University of Technology are working on a real piece of highway donated by the Dutch government, 400 meters of the A58, where they’ve discovered that this process really works, as Erik says in his talk:
"If we go on the road every four years with our healing machine — this is the big version we have made to go on the real road — if we go on the road every four years, we can double the surface life of this road, which of course saves a lot of money."
Erik is also working with microbiologist Henk Jonkers to create a “self-healing” building concrete (pictured above, on bottom), which is infused with bacterial spores and a compound that feeds these spores — calcium lactate. "When the biomaterial is exposed to water (one of the many things known to contribute to the degradation of concrete)," says io9, "the bacteria set to work converting calcium lactate into calcite, which fills in surrounding cracks."
We can’t wait to see what comes of these exciting new building materials, and until then, we’re crossing our fingers for self-healing smartphone screens.
(Bio-concrete photo via io9)